/Engine/Plugins/Developer/Concert/ConcertUI/ConcertSharedSlate/Source/ConcertSharedSlate/Public/Session/Activity/SConcertSessionActivities.h
If bound, invoked when generating a row to add an overlay to a column.
WidgetArgsType & OnMakeColumnOverlayWidget &40; const FMakeColumnOverlayWidgetFunc & InDelegate &41;